MultiSite setup problem: No stylesheet in Site / Redirect Loop in Admin

After following the Network Setup for MultiSite carefully... we have our main MultiSite working at http://homeschool-china.com/

I also installed these extras;
- WPMU DEV Dashboard
- ProSites
- Farm 33 Themes
- Anti-Splog

I can sign-up for a new site at http://homeschool-china.com/wp-signup.php

BUT...

The site looks like it is missing the stylesheet or the path is incorrect - see http://homeschool-china.com/grantclan/

I am unable to login to Admin at http://homeschool-china.com/grantclan/wp-admin/, with the following error;

This webpage has a redirect loop
The webpage at http://homeschool-china.com/grantclan/wp-admin/ has resulted in too many redirects. Clearing your cookies for this site or allowing third-party cookies may fix the problem. If not, it is possibly a server configuration issue and not a problem with your computer.
Here are some suggestions:
Reload this webpage later.
Learn more about this problem.
Error 310 (net::ERR_TOO_MANY_REDIRECTS): There were too many redirects.

I suspect that my .htaccess file is corrupted, and have tried to replace it with a sample, and then edited it to include the text provided during setup (included below);

.htaccess
ASCII text

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) home/homescho/public_html/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ home/homescho/public_html/$2 [L]
RewriteRule . index.php [L]

I look forward to your expert solution, which I hope is easy to supply.

Many thanks, Sean